package com.ddyx.common.util;

import java.io.File;  
import java.io.FileInputStream;  
import java.io.IOException;
import java.io.InputStream;
import java.nio.MappedByteBuffer;  
import java.nio.channels.FileChannel;  
import java.security.MessageDigest;  
import java.security.NoSuchAlgorithmException;  
  
import org.slf4j.Logger;  
import org.slf4j.LoggerFactory; 

/**
 * 获取文件md5值
 * @author XYZH
 *
 */
public class MD5FileUtil {

	private static final Logger logger = LoggerFactory  
            .getLogger(MD5FileUtil.class);  
    protected static char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6',  
            '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };  
    protected static MessageDigest messagedigest = null;  
    static {  
        try {  
            messagedigest = MessageDigest.getInstance("MD5");  
        } catch (NoSuchAlgorithmException e) {  
            logger.error("MD5FileUtil messagedigest初始化失败", e);  
        }  
    }  
  
    public static String getFileMD5String(File file) throws IOException {
    	FileInputStream in =null;
    	try {
    		in = new FileInputStream(file);
            FileChannel ch = in.getChannel();  
            MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0,  
                    file.length());  
            messagedigest.update(byteBuffer);
            return bufferToHex(messagedigest.digest());  
    	}finally {
    		if(in!=null)
    			in.close();
    	}
    }  
    
    public static String getFileMD5String(InputStream in) throws Exception{  
        if(in != null){
        	byte buffer[] = new byte[1024];  
            int len;
            try{
           	 while ((len = in.read(buffer, 0, 1024)) > 0) {  
           		 messagedigest.update(buffer, 0, len);  
                } 
               return bufferToHex(messagedigest.digest());
            }catch (Exception e){
            	e.printStackTrace();
            }finally{
            	in.close();
            }
        }
		return "";
    }
  
    public static String getMD5String(String s) {  
        return getMD5String(s.getBytes());  
    }  
  
    public static String getMD5String(byte[] bytes) {  
        messagedigest.update(bytes);  
        return bufferToHex(messagedigest.digest());  
    }  
  
    private static String bufferToHex(byte bytes[]) {  
        return bufferToHex(bytes, 0, bytes.length);  
    }  
  
    private static String bufferToHex(byte bytes[], int m, int n) {  
        StringBuffer stringbuffer = new StringBuffer(2 * n);  
        int k = m + n;  
        for (int l = m; l < k; l++) {  
            appendHexPair(bytes[l], stringbuffer);  
        }  
        return stringbuffer.toString();  
    }  
  
    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {  
        char c0 = hexDigits[(bt & 0xf0) >> 4];  
        char c1 = hexDigits[bt & 0xf];  
        stringbuffer.append(c0);  
        stringbuffer.append(c1);  
    }  
  
    public static boolean checkPassword(String password, String md5PwdStr) {  
        String s = getMD5String(password);  
        return s.equals(md5PwdStr);  
    }  
  
    public static void main(String[] args) throws Exception {  
        long begin = System.currentTimeMillis();  
  
        /*File big = new File("D:\\code\\ci\\resources\\src\\main\\webapp\\styles\\images\\bg_01.png");  */
        File big = new File("D:\\bg.png");  
        String md5 = getFileMD5String(big);  
        String md51 = getFileMD5String(new FileInputStream(big));
        long end = System.currentTimeMillis();  
        System.out.println("md5:" + md5);  
        System.out.println("md51:" + md51);  
        System.out.println("time:" + ((end - begin) / 1000) + "s");  
  
    }
}
